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Mysterious misfire ONLY when low HV battery, but No DTC’s

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Baz2473, Jan 23, 2019.

  1. tankyuong

    tankyuong Senior Member

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    I would rather replace the plugs
     
  2. Baz2473

    Baz2473 Junior Member

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    What, again? They’re only a week old...
     
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    If you're curious as to whether it's actually a misfire or not, Techstream should be able to give you a misfire count for each cylinder.
     
  4. tankyuong

    tankyuong Senior Member

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    Try ngk
     
  5. Baz2473

    Baz2473 Junior Member

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    Thanks for the tip. I looked into it and Techstream is showing misfires on cylinder 2 in the “View Monitors (Misfire)” section but No problem misfire DTC codes ???

    Took the egr system off again for another clean up and noticed that the intake plenum for cylinder 2 is fairly oily! Whereas all the other 3 intake plenums seem fairly dry.

    Anyone come across this before? Does it sound like intake valve stem oil seals leaking?
     
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  6. Tiff

    Tiff Junior Member

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    Baz
    Keep me posted pls. Im going through exactly the same thing. The only thing i have done is injectors. And spark plugs were genuine Toyota sc16hr11 which apparently replace sc20hr11 which i replaced 15,000 miles ago but im going to do again to rule out
    The engine feels like its gonna go bang internally when it does this and being intermittent is really mind boggling.
     
  7. Baz2473

    Baz2473 Junior Member

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    @Tiff Do you have Techstream?
     
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  8. Tiff

    Tiff Junior Member

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    Yes
     
  9. Baz2473

    Baz2473 Junior Member

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    What is your EGR flow value result in the monitor values section?

    Also

    Have you tried the EGR test procedure with it? If so, What result do you get from the MAP sensor during the test?
     
  10. Baz2473

    Baz2473 Junior Member

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    I’ve established that every time I remove the entire egr system and the intake manifold then I get a good 1000 miles of trouble free driving before the problem comes back again. I’m trying to work out what part of this process is temporary fixing it? The complete egr system is clear of all blockages (so much so that I can breathe easily through the cooler) yet when the problem comes back if I remove it all and clean it again it still seems to fix it for a week or so (1000 miles). I’ve narrowed it down to either the MAP sensor or the EGR stepper motor. (I think) argghhh!
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    That sounds very interesting, a good reason to acquire Techstream. (y)
     
  12. Raytheeagle

    Raytheeagle Senior Member

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    You got an oil catch can installed?
     
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  13. Baz2473

    Baz2473 Junior Member

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    Yep I sure do.
     
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  14. Raytheeagle

    Raytheeagle Senior Member

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    Is the coolant level stable?

    When is the last time the spark plugs have been changed?

    Have you cleaned the MAF sensor?

    What about the MAP sensor, have you cleaned that?

    When cleaning the intake manifold, is there still a puddle of spooge at the bottom?

    How much buildup is there after a thousand miles?

    Where is the catch can mounted?
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    ^ One noted anomaly. Dig into that more?
     
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  16. Baz2473

    Baz2473 Junior Member

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    Coolant stable.
    Spark plugs changed 3000 miles ago.
    MAF sensor untouched.
    MAP sensor wiped every time intake removed.
    Not really a puddle. Just a small smear.
    Hardly any buildup after 1000 miles.
    Mounted next to the inverted against the wing.
     
  17. Raytheeagle

    Raytheeagle Senior Member

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    Good catch;).

    Any oil consumption @Baz2473 ?

    I wouldn’t wipe the MAP sensor, I would just spray it with cleaner until the oil layer has been reduced.

    How are the readings on Techstream? Anything out of the ordinary or look odd?
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

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    I sprayed (and gently Q-tip wiped what I could reach through the cage, though didn't do much to clean) the MAP sensor with CRC MAF sensor cleaner. MAP sensor seems quite durable, comparing to MAF. Has to be, swimming around in the bilge at the bottom of intake manifold.
     
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  19. Raytheeagle

    Raytheeagle Senior Member

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    I’m leery about touching sensors, particularly the wired ones ;).

    Had some bad experiences at work with some of my staff messing with sensors :cool:.

    Definitely gets your attention and changes your perspective (y).
     
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  20. Tiff

    Tiff Junior Member

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    Interesing baz. How do i get into the egr flow bit on techstream and map sensor